specification does not match any archive log in the recovery catalog

Hello Everyone,
The customer is getting the following on Hp-UX Itanium platform and on 10.2.0.5 database version:

We sometimes get the following message in our RMAN logs.

specification does not match any archive log in the recovery catalog

It is not obvious what it means. Plese clarify the meaning. Also, is this a cause for concern.

I could not find the error code in the directory where we keep the RMAN logs.

grep RMAN-20242 *
Returns nothing.

I found 122 cases with the error text with out the "RMAN-20242"

grep 'specification' * | wc
122 1342 14587

grep 'specification' *
ora.env_backup.20120107.152001.9334.sa.log.xxxxx:specification does not match any archive log in the recovery catalog